Spotlight on: Radiation and the Heart

Cancer treatments are
designed to target cancer cells, but often they take a toll on the rest of the
body as well. For some patients undergoing radiation therapy, the condition of
the heart may be compromised. At UVA’s new Emily Couric Clinical Cancer Center,
advances are being made to lessen the effects of radiation on the heart, while
still effectively treating the cancer. UVA radiation oncologist Paul Read, MD,
PhD, shares his insight on this important topic.

Q. How can radiation treatment damage the heart?

The most common risk of
heart injury from radiation occurs in patients who have breast cancer on the left
side. Although very little heart muscle may be irradiated during treatment, an
important artery—known as the left anterior descending (LAD) artery that runs
down the front part of the heart—may be in the path of radiation beams. This
exposure can result in accelerated atherosclerosis (hardening of the arteries)
or coronary artery disease (narrowing of the small vessels to the heart), which
may appear 15-20 years after treatment.

If a large volume of the
heart is irradiated (to doses of 40 Gy or higher), the sack covering the heart
called the pericardium can become fibrotic (restrictive pericarditis) or filled
with fluid (radiation inflammatory pericarditis), or the heart muscle itself
can become weakened (radiation myocarditis), resulting in congestive heart
failure.

Fortunately, large volumes
of the heart are rarely irradiated, but sometimes this can happen when treating
patients who have large, left-sided lung cancers or mesotheliomas. These
effects can occur six months to several years after radiation treatment.

Q. What symptoms should cancer patients be aware of
to spot a developing problem with their heart?

They should be aware of the
symptoms of congestive heart failure (shortness of breath, swelling of the
feet) or coronary artery disease (angina, chest pressure, shortness of breath,
sweating, left arm or jaw pain, fatigue).

Q. How is UVA working to protect the heart during
radiation treatment?

When we treat cancer
patients with radiation, we do everything possible to avoid treating the heart
by using sophisticated delivery techniques. We have several of the most
advanced radiation systems in the world. Our radiation oncology team, including
Krishni Wijesooriya, PhD, and Monica Morris, MD, is working on groundbreaking
techniques to reduce radiation to the heart when treating left-sided breast
cancer patients.

We use a treatment
technique known as Deep Inhalation Breath Hold. We’ve presented our methods and
results for using this treatment at several national meetings. The basic idea
is to treat left-sided breast cancer patients while they take a deep breath.
This separates the breast or chest wall from the heart so that the heart and
LAD artery are not in the path of radiation beams.

Modern radiation delivery
units that can deliver the radiation quickly are required. Special CT scans
during the planning phase capture images when the patient takes a deep breath.
We measure the patient’s breathing and show the patient how deep they are
breathing using special biofeedback goggles. This way, patients know at what
depth they should hold their breath for each daily treatment. All of this makes
the treatment process extremely precise.